Internal-combustion engine



Sept 8, 1925. 1,552,819 A. P. BRUSH ET AL INTERNAL COMBUSTI ON ENGINE Filed Aug. 13. 1920 I l 7' I i if I 75 1 v I] I v I l 1" 1| H :l E 1 1' I {I 2 '1 I 70 v Q hf lwvwt u Patented Sept. 8 1925.

UNITED STATES PA 1,552,819 TENT OFFICE.

v ALANSON P. BRUSH AND OWEN M. HACKER, OF DETROIT, MICHIGAN.

' INTERNAL-COMBUSTION ENGINE.

Application filed. August 13, 1920. Serial No. 403,183.

To all whom it may concern Be it'known that we, ALANSON P. .BRUsH and OWEN M. NACKER, both citizens of the United States of America, residing at Detroit, in the county of Wayne and State of 'Michigan, have invented certain new and useful Improvements in Internal-CombustionEngines, of which the following is a specification, reference being had therein to t e accompanying drawings.

The modern internal combustion engine of the 4-cycle type, when adapted to service which requires awide range of speed and power output, is ordinarily controlled principally by throttling the amount of mixture of air and fuelsupplied to the combustion chambers.

Ar engine of this type, when used for this kind. of service, as for examplethe modern motor vehicle, has several undesirable characteristics. Among them are First-The tendency to'suck lubricating oil past the, pistons into the combustion chambers when the controlling throttle is nearly closed. This isdue to the comparatively high vacuum on the suction strokes under the conditions outlined, and s com- 'monly called oil pumping.

Second-If an engine of this type is provided with suflicient cooling means to maintain it at proper operating temperature when it is producing high power outputs, it cools down below proper operating temperature when running wlth a nearly closed throttle for low power'outputs. I

Third-Because of the undesirable low temperature of the engine when operatin at low power outputs, thereis apt to be a ailure bothin the manifold'and 1n the combustion chambers of the engine to vaporize some of the fuel supplied to the engine with the result that such unvaporized fuel is not com pletely burned, resulting in a waste of fuel and in the contamination of the lubricating oil by such unvaporized fuel, finding its way past the pistons into the crankcase of the engme.

This difliculty of unvaporized fuel is further aggravated in a multiple 0 linden engine, because of the low air ve ocity In a manifold supplying" several cylinders from.-

one carburetor-some cylinders receive more fuel than others-and permits an accumulation of fuel within the manifold, when the englne is operating with a nearly closed throttle, which accumulation of fuel is thrown into the combustion chambers of the en ine when the throttle is opened.

ourthIn a multiple cylinder engine involving the use of a manifold to supply the several cylinders with fuel and air mixture from one carburetor,fif the manifo d is large enough to supply an adequate amount of mixture to the several cylinders for .high

power outputs at high speed, then when operating with a nearly closed throttle for low power outputs or low speeds, the air velocity within the manifold becomes too low to permit the manifold to function with fuels of low volatility; that is, with fuels that do not entirely vaporize befo e introduction to the cylinders.

The pre ent invention overcomes these difficulties by a si. ople modification, which consists essentially in means for introducing a small portion of the exhaust gases into the intake in proportion to the restriction thereof. The gases so introduced have the effect; first, of dlminlshing'the high vacuum, and

reducing the tendency to suck oil past the pistons, second, the heat of the introduced gases W111 partly compensate for the lowered cat generation and tend to maintain more uniform temperature conditions in the engine cylinders,-it will alsoassist in the va porization of the liquid fuel in the manifold; third, the velocity of the gases passing through the manifold is increased by the added volume of gas, which lessens the tend- (no for the liquid to fall out of suspension.

ur invention may be embodied in various constructions, but in the drawings it is shown more or less diagrammatically, in which- Figure 1 is a section through an internal combustion engine; and v Figure 2 is a cross-section through the intake and exhaust conduits, showing a modified construction.

A is the combustion chamber of an internal combustionengine, B is the intake passage controlled by the valve 0, and D is the exhaust passage controlled by the valve E. F represents diagrammatically a i carburetor havmg the fuel jet -Gr, and H is the throttle. Our invention is applied to the engine by a simple by-pass connection I between the exhaust conduit and intake, the po nt'of attachment to the latter being referably before the first sub-division o the manifold and preferably adjacent to the throttle on the vacuum side thereof. This by-pass is controlled by a valve J, which as shown in Figure 1 is mechanically connected with the throttle through the rock arms K andL and the connecting link M. The construction is such that when the throttle is. moved from open to closed or idling position, the valve J will be correspondingly moved from closed to open position. Thus, the amount of exhaust gases introduced is varied according to the position of the throtas and, as before stated, will tend to reduce the high vacuum to increase the velocityof the gases in the manifold and will modify extreme variations in temperature.

With the modified construction shown in Figure 2, in place of a mechanical connection between the valve controlling the bypass and the throttle, an automatically operating valve is substituted. This, as shown, consists of a piston valve N having its outer end exposed to atmospheric pressure and its inner end exposed to the pressure of the intakc manifold. O is a port through the valve adapted for registration with the by-pass I, and P is a springfor yieldably, pressing the valve outward into a position where the port 0 is closed.- P is a stop for' limiting the stroke of the piston valve. Thus, in operation, whenever the vacuum in the intake manifold is increased, the. valve N will be moved towards open position, whifih will admit exhaust gases into the intake.

As above stated, the advantages of introducing a variable quantity of inert as into the combustible mixture are, first, t at the vacuum in the cylinder is reduced, thereby avoiding the sucking in of oil; second, the velocity of the gases passing through the intake manifold, particularly in a multi-- cylinder engine, will be increased, which will prevent the falling out of the fuel from susof the fuel inlet. In other words, to avoid I interfering with the function of the carburetor, and the proper proportioning of the fuel to the air, the inert gases must be introduced on the engine side of the fuel inlet.

What we claim as our invention is:

1. The combination with an internal combustion engine, including intake and exhaust conduits, of a throttle controlling the intake conduit, a by-pass connection between the exhaust conduit and intake conduit connecting with the latter adjacent to said throttle on the engine side thereof, a valve for controlling said by-pass, and a mechanical connection between said valve and throttle by which the by-pass is opened as the throttle is closed.

2. The combination with an internal combustion engine including intake and exhaust conduits, of a throttle controlling the intake conduit, a by-pass connection between the exhaust conduit and intake conduit connecting with the latter adjacent to said throttle on the engine side thereof, a rotary valve for controlling said by-pass, an arm connected to said valve, a second arm connected to said throttle, and a link connecting ,said arms whereby the by-pass is opened as the throttle is closed.

In testimony whereof we affix our signatures.

ALANSON P. BRUSH. -OWEN M. NACKER. 

